U.S. patent application number 10/945788 was filed with the patent office on 2005-02-17 for seat back for a vehicle seat comprising an integrated protective device.
This patent application is currently assigned to Johnson Controls Technology Company. Invention is credited to Hake, Ernst-Jurgen, Muller, Hans-Joachim, Schmale, Gerhard, Strieder, Lutz.
Application Number | 20050035642 10/945788 |
Document ID | / |
Family ID | 7918627 |
Filed Date | 2005-02-17 |
United States Patent
Application |
20050035642 |
Kind Code |
A1 |
Hake, Ernst-Jurgen ; et
al. |
February 17, 2005 |
Seat back for a vehicle seat comprising an integrated protective
device
Abstract
The invention concerns a seatback for a vehicle seat, having an
integrated protective device. The protective device includes a
device that generates a torque acting in a pivoting direction on an
upper back part, a rear-end impact detector that is-in effective
connection with the torque-generating device in such a way that the
device is activated in the event of the rear-end impact and the
pivoting motion is initiated, and an immobilization device for
retention of the upper back part in the normal use position.
Inventors: |
Hake, Ernst-Jurgen;
(Rodevormwald, DE) ; Muller, Hans-Joachim;
(Bergisch Gladbach, DE) ; Schmale, Gerhard;
(Huckoswagen, DE) ; Strieder, Lutz; (Remscheid,
DE) |
Correspondence
Address: |
FOLEY & LARDNER
777 EAST WISCONSIN AVENUE
SUITE 3800
MILWAUKEE
WI
53202-5308
US
|
Assignee: |
Johnson Controls Technology
Company
|
Family ID: |
7918627 |
Appl. No.: |
10/945788 |
Filed: |
September 21, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10945788 |
Sep 21, 2004 |
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10049698 |
Jun 24, 2002 |
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6802562 |
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10049698 |
Jun 24, 2002 |
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PCT/EP00/07995 |
Aug 16, 2000 |
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Current U.S.
Class: |
297/396 |
Current CPC
Class: |
F16B 39/282 20130101;
B60N 2/815 20180201; B60N 2/853 20180201; B60N 2/847 20180201; B60N
2/888 20180201 |
Class at
Publication: |
297/396 |
International
Class: |
A47C 001/10 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 17, 1999 |
DE |
199 38 904.7 |
Claims
What is claimed is:
1. A seatback for a vehicle seat, the seatback having an integrated
protective device, comprising: a lower back part adapted to be
joined to a seat part; an upper back part that is pivotable
relative to the lower back part out of a normal use position, about
an axis extending in the seatback transversely to a longitudinal
vehicle axis, through an angular range in a pivoting direction
pointing in a direction of vehicle travel, as a result of a torque
acting in the pivoting direction, into a safety position; a device
for generating the torque; means for detecting a rear-end impact;
and immobilization means for retention of the upper back part in
the normal use position; wherein the device for generating the
torque comprises a force storage device or an energy storage device
acting irrespective of any occupancy of the vehicle seat, the means
for detecting a rear-end impact comprising a vehicle crash sensor
and the immobilization means comprising a lever system, the vehicle
crash sensor being in effective connection with the force storage
device or the energy storage device, and with the lever system
constituting the immobilization means for retention of the upper
back part, such that in the event of the rear-end impact, the
retention of the upper back part in the normal use position is
nullified, the force storage device or the energy storage device is
activated, and the upper back part is pivoted in the pivoting
direction.
2. The seatback of claim 1, wherein there is attached in or on the
upper back part a headrest which in the event of a rear-end impact
is moved out of a comfort position, in which a spacing between the
headrest and a seat user's head is approximately 40 to 110 mm, into
an interception position, in which the spacing between the headrest
and the seat user's head is zero or almost zero.
3. The seatback of claim 1, further comprising a second
immobilization means for retention of the upper back part against a
backward motion out of the safety position into the normal use
position.
4. The seatback of claim 1, wherein the lever system of the
immobilization means for retention of the upper back part in the
normal use position comprises an interlock lever joined immovably
to the upper back part, and to the torque-generating device, the
interlock lever pivotable about the pivot axis of the upper back
part, and secured in a locked position by a locking bolt.
5. The seatback of claim 4, wherein in the locked position, the
locking bolt engages through an elongated opening of the interlock
lever, out of which it is moved in order to release the
torque-generating device.
6. The seatback of claim 4, wherein the torque-generating device is
a torsion spring and wherein the interlock lever is joined to the
torsion spring via a recoil lock that blocks any pivoting of the
upper back part in the direction out of its normal use position
into its safety position, but permits it in the opposite
direction.
7. The seatback of claim 6, wherein the recoil lock is embodied as
a self-locking rolling-element or wedge-type lock, operating
positively or nonpositively, preferably by jamming, or as a ratchet
device, in such a way that it makes possible immobilization even in
positions located between the safety position and the normal use
position of the upper back part.
8. The seatback of claim 3, wherein the second immobilization means
is respectively embodied as a self-locking rolling-element or
wedge-type lock that operates positively and/or nonpositively, or
as a ratchet device, the second immobilization means making
possible immobilization against a backward motion even in positions
located between the safety position and the normal use position of
the upper back part.
9. The seatback of claim 3, wherein the second immobilization means
is configured as a rolling-element locking device comprising a ring
gear, arranged concentrically about the pivot axis of the upper
back part, that is arranged inside a cylindrical shell, as well as
rolling elements arranged between the teeth of the ring gear and
between the ring gear and the shell.
10. The seatback of claim 3, wherein the second immobilization
means is configured as a recoil lock that comprises a cylindrical
inner part, arranged concentrically about the pivot axis of the
upper back part, that is arranged within a shell part, as well as
rolling elements or jamming wedges arranged in receptacles of the
shell part.
11. The seatback of claim 3, wherein the second immobilization
means is configured as a recoil lock that comprises a cylindrical
inner part having a smooth enveloping surface or one structured to
increase friction or equipped with a coating, and an eccentrically
mounted pivoting body engaging nonpositively on the enveloping
surface of the inner part.
12. The seatback of claim 3, wherein the second immobilization
means is configured in such a way that the second immobilization
means limits any recoil play of the upper back part to a maximum
angular magnitude of one degree.
13. The seatback of claim 1, wherein the means for detecting a
rear-end impact are in effective connection with the immobilization
means for retention of the upper back part in the normal use
position, and the immobilization means are in effective connection
with the torque-generating device, in such a way that in the event
of the impact, a release of the torque-generating device is
accomplished by the immobilization means by means of a pyrotechnic
device.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This application is a divisional of U.S. application Ser.
No. 10/049,698, which was the National Stage of International
Application No. PCT/EP00/07995, filed Aug. 16, 2000, which claimed
the benefit of German Application No. 199 38 904.7, filed Aug. 17,
1999, all of which are incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention concerns a seatback for a vehicle
seat, having an integrated protective device against
accident-related injuries in the event of a rear-end impact, in
particular against cervical vertebra syndrome or acceleration
trauma, having a lower back part joined to a seat part and having a
upper back part that is pivotable relative to the lower back part
out of a normal use position, about an axis extending in the
seatback transversely to the longitudinal vehicle axis, through an
angular range in a pivoting direction pointing in the direction of
travel, as a result of a torque acting in the pivoting
direction.
BACKGROUND OF THE INVENTION
[0003] Many present-day developments in automotive engineering are
aimed toward using available materials and design methods to make
the seatbacks of vehicle seats lightweight but highly rigid, in
order (despite the light weight) to withstand the large stresses
that occur in an accident event and to sufficiently support the
body of the vehicle occupant. The result of this, however, is that
for example even in a so-called "fender-bender" accident or
low-speed crash at low velocities in the range from 10 to 30 km/h,
in which the body experiences an acceleration of approx. 8 to 20 G,
damage to the body's neck musculature and cervical vertebrae can
occur, since the impact force acts in almost undamped fashion on
the person. An undesirable effect, called the "whip effect," occurs
on the head and neck, resulting in hyperextension and overstressing
of the cervical vertebrae and support muscles of the head. This
effect, and the spinal column injuries possible in particular in
the neck region, are also referred to using the English term
"whiplash."
[0004] Passive and active apparatuses are known for protection
against these injuries; the latter, in the event of an accident,
are intended to actively decrease the distance between the person's
head and the headrest of the seatback. One such known (active)
apparatus of the kind cited above is described in DE 197 43 339 A1.
In this context, the body of the vehicle occupant (seat user)--
which in the event of an impact relative to the direction of travel
is bent backward or accelerated, as a result of its inertia, into
the seatback of the vehicle seat--encounters an impact panel that
is mounted below the pivot axis of the upper back part and is
joined pivotably to the upper back part, in particular to a
headrest on the back part. The relative motion of the impact panel
toward the rear causes the headrest to pivot forward. The motion of
the headrest is intended to mitigate the whiplash effect.
[0005] It is disadvantageous in this context that the relative
motion of the headrest does not occur until the occupant is thrown
into the seatback. As a result, the upper back part can be
accelerated only by a value that is equal, at most, to the
acceleration value experienced by the vehicle seat as a result of
the impact. Since the motion characteristics of the seat user
cannot be accurately predicted in every case, however, in some
circumstances the active counter-motion of the seatback or headrest
may in fact cause incorrect, undesired, possibly dangerous effects.
For example, the impact of the occupant's head can in fact be
further amplified, and occupant "ramping" (vertical movement in the
seat) also cannot be prevented. This is because in a rear-end
impact, the occupant is accelerated into the seatback (which is
usually tilted backward out of the vertical) in such a way that he
or she tends to rise up along the seatback as if it were a ramp.
This generally results in failure of the seatback, which buckles
due to overload and is no longer capable of supporting the
occupant. In particular, the seat user's head can end up at a
height which is above the headrest, where it can no longer be
supported. A considerable residual accident risk thus exists with
the known seatback.
[0006] Mechanisms that are triggered by displacement of the vehicle
occupant's body into the seatback opposite to the direction of
travel do not exhibit the desired protective effect. The differing
heights and therefore weights of vehicle users prove to be a
particular disadvantage. Because of this, it is impossible to
ensure reliably that the triggering device of a protective device
is correct and effective. A further uncertainty factor is the
delayed reaction of the previously disclosed mechanisms of this
type. The configuration of the upholstery of the seatback also
plays an important part; it should be as thin as possible in the
region of the triggering device. This would in turn, however,
result in an undesirable degradation of upholstery comfort.
[0007] It has therefore been proposed in German Patent Application
199 38 904.7 that reliable triggering of the protective device be
performed, irrespective of the vehicle occupant's build, at a
minimum acceleration which can be measured, for example, at the
vehicle seat. In the case of a small car, the measured acceleration
value is reached at a considerably lower impact speed than is the
case for a sedan with a large absorbing crumple zone, or for a
truck. The proposed protective device has on the one hand a device
that, irrespective of the occupancy of the vehicle seat, generates
the torque acting in the pivoting direction on the upper back part;
on the other hand it comprises means for detecting a rear-end
impact that are in effective connection with the torque-generating
device in such a way that the device is activated in the event of
the rear-end impact and the pivoting motion is initiated. Also
provided in this context are immobilization means for retention of
the upper back part in the normal use position, and immobilization
means for retention of the upper back part against a backward
motion out of the safety position into the normal use position.
[0008] It is the object of the present invention to create, using
means of little design complexity, a seatback of the aforesaid kind
whose protective device guarantees improved protection of the
respective seat user against injury, in particular by way of an
improved interception capability and damping when the head and
upper body of the person present on the seat strike the headrest
and seatback. The intention is to implement, in particular in the
normal use position and additionally in the safety position, an
effective immobilization system that nevertheless does not impede
the triggering operation.
SUMMARY OF THE INVENTION
[0009] The object of the invention is achieved by a seatback of the
kind cited initially in which the protective device comprises at
least the following parts:
[0010] a device that, irrespective of any occupancy of the vehicle
seat, generates the torque acting in the pivoting direction on the
upper back part;
[0011] means for detecting a rear-end impact that are in effective
connection with the torque-generating device in such a way that the
device is activated in the event of the rear-end impact and the
pivoting motion is initiated; and
[0012] immobilization means for retention of the upper back part in
the normal use position, the immobilization means being constituted
by a lever system, and the means for detecting a rear-end impact
being in effective connection with the immobilization means for
retention of the upper back part in the normal use position in such
a way that in the event of the impact, the retention of the upper
back part in the normal use position is nullified.
[0013] According to the present invention, in particular because of
the unlocking of the lever system, pivoting of the upper back part
can preferably proceed so quickly that the upper back part is in
the safety position before the onset of any head motion of the seat
user resulting from the rear-end impact. In the safety position,
the upper back part rests directly against the seat user's body so
that the user, despite the acceleration acting on him or her due to
the impact, advantageously can no longer freely move backward
against the vehicle's direction of travel and incur accidental
injuries.
[0014] In the context of the seatback according to the present
invention, it is particularly advantageous in terms of the
efficiency of the protective device if a headrest is attached in or
on the upper back part. It is useful in this context to mount the
headrest, which as a rule is guided on holding rods for adjustment
of the vertical position, in the backrest at the height of the
shoulder region tiltably about an axis extending transversely to
the vehicle axis. For this purpose, for example, an upper
crossmember of the seatback can be attached in upper portions of
the side members of the seatback by means of a pivot bearing. The
upper back part can also, however, be configured in such a way that
it assumes the function of a headrest. In any event, the person
using the vehicle seat can as a result move uniformly into the
seatback with decelerating energy absorption by the vehicle seat,
with particular protection of the neck and head region. The result
is that when the normal use position of the seatback exists, the
headrest is in a so-called comfort position in which its spacing
from a seat user's head can be approximately 40 to 110 mm. As a
result of the pivoting motion of the upper back part, the headrest
is then transferred into a so-called interception position, in
which its spacing from a seat user's head is zero or almost zero.
The normal use position and safety position of the upper back part
thus correspond, when a headrest is present, to the latter's
comfort position and interception position.
[0015] It is advantageous to provide a force storage device or
energy storage device as the torque-generating device for the
pivoting motion of the cross member carrying the headrest. A
preloaded torsion spring, in particular, has proven advantageous in
this context, since it possesses a very low intrinsic acceleration
and therefore requires less installation space for the same effect
as compared to tension or compression springs.
[0016] The lever system of the immobilization means for retention
of the upper back part in the normal use position can preferably
comprise at least two coacting levers. A first lever (hereinafter
called the pawl) can brace the pivotable crossmember, preloaded by
the torsion spring, with respect to a stationary counterbearing;
while a second lever (hereinafter called the immobilization lever)
acts as immobilizer for the pawl. In the event of a rear-end
impact, the immobilization lever is pivoted in such a way that it
releases the immobilization of the pawl. Triggering of the
immobilization lever can be effected with a very low actuation
force, thereby making possible a very fast lever movement and thus
rapid unlatching of the pawl.
[0017] Actuation of the immobilization lever can preferably be
accomplished with an electromagnet which obtains its pulse from a
sensor, such as an acceleration sensor, that is used as a means for
detecting the rear-end impact.
[0018] After release of the pawl, the latter pivots out of its
bracing position; and the crossmember of the seatback, with the
headrest, can move in the direction of the back of the vehicle
occupant's head.
[0019] After a triggering of the protective device, the latter can
be brought back into its initial position by once again activating
the device that generates the torque acting on the upper back part
(e.g. by tensioning the torsion spring); for safety reasons, this
operation is to be performed only in a repair shop, in which seat
functionality after a crash can concurrently also be checked.
[0020] It is particularly advantageous, in terms of reliably
preventing a spring-back or bounce-back effect when the protective
device takes effect, if the immobilization means for retention of
the upper back part against a backward motion from the safety
position into the normal use position (which means are also
referred hereinafter to as the "recoil lock") are embodied so that
they make possible immobilization not only in the normal use
position and in the safety position, but also in multiple positions
located therebetween. This can be implemented, for example, by
means of self-locking rolling-element or wedge-type locks that
operate positively or nonpositively (preferably by jamming), or by
means of a ratchet device. A suitable design of the recoil lock
advantageously makes it possible to limit any recoil play of the
upper back part (motion in the direction of the safety position) to
a maximum angular magnitude of 1 degree.
[0021] Further advantageous embodiment features of the invention
are contained in the dependent claims and in the description
below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The invention will be explained more thoroughly, by way of
example, with reference to the drawings, in which:
[0023] FIG. 1 is a perspective, partially schematic side view of a
seatback according to the present invention;
[0024] FIG. 2 is a side view of a preferred embodiment of a
seatback, with a depiction of a seat user;
[0025] FIG. 3 is a perspective depiction of the upper part of the
seatback according to the present invention depicted in FIG. 2;
[0026] FIG. 4 is a sectional side view through the upper part of
the seatback according to the present invention depicted in FIG. 3,
in a central region (plane IV-IV-IV-IV);
[0027] FIG. 5 shows a further embodiment of a seatback according to
the present invention in a sectioned side view corresponding to
FIG. 4;
[0028] FIGS. 6 through 8 show three further embodiments of the
immobilization means for retention of the upper back part against a
backward motion out of the safety position into the normal use
position of a seatback according to the present invention, in a
sectioned side view corresponding to FIGS. 4 and 5;
[0029] FIG. 9 is a perspective view of an upper part of a further
preferred embodiment of a seatback according to the present
invention;
[0030] FIG. 10 is a side view of the embodiment depicted in FIG. 9
of a seatback according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] In the various Figures of the drawings, identical parts are
always given the same reference characters, so that as a rule each
is also described only once.
[0032] As is evident firstly from FIG. 1, a vehicle seat 1
comprises a seatback 2 according to the present invention and a
seat part 3. Integrated into seatback 2 is a protective device that
serves to protect the person in question against accident-related
injuries, in particular cervical vertebra syndrome or acceleration
trauma in the event of a rear-end impact. Seatback 2 has a lower
back part 4 joined to seat part 3, and an upper back part 5 that is
pivotable relative to lower back part 4 out of a normal use
position (drawn with solid lines in FIG. 1), about an axis X-X
extending in seatback 2 transversely to the longitudinal vehicle
axis, through an angular range in a pivoting direction S pointing
in direction of travel F into a safety position (drawn with
dot-dash lines in FIG. 1), as a result of a torque acting in
pivoting direction S.
[0033] According to the present invention, the protective device
comprises on the one hand a device 6 that, irrespective of any
occupancy of the vehicle seat 2, generates the torque (arrow M in
FIG. 1) acting in pivoting direction S on upper back part 5, and on
the other hand comprises means 7 for detecting a rear-end impact.
Both torque-generating device 6 and detection means 7 can be
differently configured. These parts of seatback 2 according to the
present invention are therefore shown merely schematically (as
boxes) in FIG. 1.
[0034] Torque-generating device 6 can advantageously, for example,
be constituted by a force storage device or energy storage device,
in particular by a preloaded spring element or multiple preloaded
spring elements. In the various embodiments of the invention that
are depicted in the further Figures, the torque-generating device
is embodied as a leaf-shaped torsion spring (torsional spring 6a)
lying in pivot axis X-X of upper back part 5 that extends
transversely to the longitudinal vehicle axis, which spring
advantageously has a very low intrinsic acceleration and requires
little installation space for the same effect as compared to
tension or compression springs (cf. especially FIG. 3).
[0035] Means 7 for detecting the rear-end impact can advantageously
be constituted by a vehicle crash sensor, such as an acceleration
sensor. To detect a so-called low-speed crash, the vehicle crash
sensor can be adjusted in such a way that it responds at an
acceleration a of approximately 40 to 80 m/s2. As already
mentioned, the acceleration value at which the sensor responds is
based on the type and configuration of a particular motor vehicle
(small car, sedan with absorbing crumple zone, truck).
[0036] Detection means 7 can be in effective connection with
torque-generating device 6 in such a way that device 6 activates in
the event of the rear-end impact and the pivoting motion of upper
back part 5 is initiated. Lower back part 4 remains in its original
(normal use) position.
[0037] In order to ensure optimum protection of the seat user,
lower back part 4 and upper back part 5 can preferably be matched
in defined fashion to one another in terms of their respective
lengths (not characterized further); and axis X-X extending
transversely to the longitudinal vehicle axis, about which upper
back part 5 is pivotable, can be arranged at a defined height H in
the shoulder region of a seat user, preferably approximately 400 to
580 mm above seat part 3.
[0038] Attached in or on upper back part 5 is a headrest 8 that in
the event of a rear-end impact is moved out of a comfort position
(drawn with solid lines in FIG. 1), in which its spacing (A1 in
FIG. 2) from a seat user's head is approximately 80 to 120 mm, into
an interception position (drawn with dot-dash lines in FIG. 1), in
which its spacing (A2 in FIG. 2) from a seat user's head is zero or
almost zero.
[0039] Also provided are immobilization means 9 for retention of
upper back part 5 in the normal use position. The retention is
illustrated by arrow A in FIG. 1. As will be described in further
detail below with reference to FIGS. 3 through 5, these
immobilization means 9 are constituted by a lever system. Arrow B
in FIG. 1 indicates that immobilization means 9 can block the
action of torque-generating device 6.
[0040] Means 7 for detecting a rear-end impact are in effective
connection (arrow U in FIG. 1) with immobilization means 9 for
retention of upper back part 5 in the normal use position in such a
way that in the event of the impact, retention A of upper back part
5 in the normal use position, and blocking B of torque-generating
device 6, are nullified.
[0041] Further immobilization means 10, whose effect is illustrated
by arrow K in FIG. 1 and which are explained in more detail below
with reference to FIGS. 4 through 8, can advantageously be provided
to retain upper back part 5 against a backward motion out of the
safety position into the normal use position.
[0042] In the embodiment of the invention just described, the
protective device against accident-related injuries, integrated
into seatback 2 and not further characterized as a whole, is thus
constituted by: lower back part 4; upper back part 5, pivotable
about axis X-X, having headrest 8; torque-generating device 6;
means 7 for detecting a rear-end impact; immobilization means 9,
configured as a lever system, for retention of upper back part 5 in
the normal use position; and immobilization means 10 for retention
of upper back part 5 against a backward motion out of the safety
position into the normal use position.
[0043] FIG. 3, which shows an enlarged detail of seatback 2
according to the present invention depicted in FIG. 2 in the region
of the transition from lower back part 4 to upper back part 5,
illustrates a preferred concrete embodiment for device 6 which,
irrespective of any occupancy of vehicle seat 2, generates torque M
that acts in pivoting direction S on upper back part 5; for
immobilization means 9, configured as a lever system, for retention
of upper back part 5 in the normal use position; and for
immobilization means 10 (recoil lock) for retention of upper back
part 5 against backward motion out of the safety position into the
normal use position.
[0044] As has already been mentioned, torque-generating device 6 in
FIG. 3 is configured as a preloaded spring element, specifically as
a leaf-shaped torsion spring 6a mounted in upper back part 5. With
a torsion spring 6a of this kind, it is advantageously possible to
generate very high displacing forces or a very high torque M, which
enables pivoting of upper back part 5 in a matter of milliseconds.
It has proven advantageous for the spring element if it exhibits a
descending characteristic curve that exhibits high initial force to
generate strong acceleration, but only a very low final force. This
takes into account particularly the fact that because of its
arrangement in the vehicle, upper back part 5 experiences as a
result of the crash an acceleration that goes against the action of
the spring element. It is, in particular, extremely advantageous if
torque-generating device 6 is designed in such a way that in the
event of its activation, upper back part 5 is accelerated in
pivoting direction S at a magnitude greater than a measured (or,
preferably, an empirically determined) average magnitude of
acceleration a that vehicle seat 2 experiences because of the
rear-end impact; this can be adjusted by way of the spring
characteristic curve (thickness and material of torsion spring
6a).
[0045] Visible in FIG. 3, as known per se, are holding rods 8a, 8b
of headrest 8 that are provided for adjusting the vertical
position, by means of which headrest 8 is mounted in seatback 2 at
the height of the shoulder region of a seat user, tiltably about an
axis X-X extending transversely to the vehicle axis (see H in FIG.
1 regarding the vertical location of axis X-X). For this purpose,
an upper crossmember 5a of seatback 2 that carries holding rods 8a,
8b is mounted pivotably (pivoting direction S) about axis X-X in
which torsion spring 6a lies, in respective upper attachment
segments 4a that project beyond lower back part 4 on two side
members 4b immovably joined to lower back part 4. Torsion spring 6a
itself is clamped laterally at its ends in attachment segments 4a
and immovably joined to crossmember 5a approximately centeredly via
a holding part 6b. It can thus be preloaded in the normal use
position (depicted exclusively in FIG. 4 and as one position in
FIG. 5) by a pivoting movement opposite to the indicated pivoting
direction S.
[0046] Provided as immobilization means 9 for retention of upper
back part 5 in the normal use position is a lever system which is
carried by two side walls (not further designated) of holding part
6b (configured, in particular, as a pocket) and which acts as a
positive or nonpositive lock.
[0047] In the embodiments depicted, as shown in more detail by FIG.
4 and in particular FIG. 5 as well, the lever system comprises two
coacting levers 9a, 9b that are mounted pivotably in holding part
6b. A first lever (pawl 9a), in particular of one-armed
configuration, is mounted laterally in bearings 9c of holding part
6b (in which context bearing axis Y-Y extends parallel to rotation
axis X-X of upper back part 5), and braces pivotable crossmember
5a, which is preloaded by torsion spring 6a, against a stationary
counterbearing 4c. Counterbearing 4c is located at the upper end of
a support part 4d that is immovably joined at the other end to
lower back part 4 and projects into pocket-like holding part 6b,
and is constituted by a stop surface for a lobe 9d of pawl 9a
arranged approximately at the unattached lever end. In a locked
position of pawl 9a, lobe 9d rests against counterbearing 4c.
[0048] The second lever (immobilization lever 9b), in particular of
two-armed configuration, serves to lock pawl 9a in its locked
position. It is mounted laterally in bearings 9e of holding part 6b
(in which context bearing axis Z-Z once again extends parallel to
rotation axis X-X of upper back part 5), and in its locked position
engages with a locking lobe 9f positively into pawl 9a in such a
way so that the latter cannot move out of its locked position. The
depictions in FIGS. 4 and 5 each show the locked positions of pawl
9a and immobilization lever 9b.
[0049] If the requirement occurs (i.e. a rear-end impact),
immobilization lever 9b is pivoted about its bearing axis Z-Z
(clockwise in the depictions of FIGS. 4 and 5), the positive
engagement of locking lobe 9f into pawl 9a being nullified and pawl
9a being released for a pivoting motion about its axis Y-Y (also
clockwise in the depictions of FIGS. 4 and 5). Triggering of
immobilization lever 9b can be accomplished with a very small
actuation force acting at one lever end 9g, and advantageously is
brought about by means of an electromagnet (not depicted) which
receives its switching pulse from a sensor (constituting means 7
for detection of the rear-end impact).
[0050] Once pawl 9a has been released by immobilization lever 9b,
it is pivoted (clockwise in accordance with the selected
depiction), solely by the action of torsion spring 6a, about its
bearing axis Y-Y out of its locked position into its released
position. In that context, the friction between the stationary stop
surface of counterbearing 4c and the support surface on lobe 9d of
pawl 9a is overcome. Crossmember 4a pivots with headrest 8 in the
direction of the back of the vehicle occupant's head (interception
position of headrest 8). The positions assumed in this context by
upper back part 5 and headrest 8 are drawn with dot-dash lines in
FIG. 1, as already mentioned, and are labeled in FIG. 5 (for the
second preferred embodiment of the invention) with dot-dash
reference lines.
[0051] Alternatively to the sensor embodiment, means 7 for
detecting the rear-end impact could also be constituted by a
mechanical control system that comprises mechanical parts which,
accelerated by the action of the rear-end impact, bring
immobilization lever 9b out of engagement, i.e. into an unlocked
position. This, too, corresponds to a direct effective connection U
from means 7 for detecting the rear-end impact to immobilization
means 9.
[0052] As shown in FIGS. 3 through 8, a variety of embodiments are
possible as immobilization means 10 for retention of upper back
part 5 against a backward motion of upper back part 5 out of the
safety position into the normal use position, and of headrest 8 out
of the interception position into the comfort position.
[0053] It has already been mentioned earlier that in order to
suppress a spring-back or bounce-back effect upon activation of the
protective device, said immobilization means 10 (recoil lock) are
embodied in such a way that they allow immobilization not only in
the normal use position and the safety position of upper back part
5, but also in positions located therebetween. As is clear from the
various embodiments of the recoil lock described below, this can be
achieved, for example, by means of self-locking rolling-element or
wedge-type locks that operate positively and/or nonpositively
(preferably by jamming), or by means of a ratchet device. For the
embodiments of the recoil lock that are described it is
advantageously possible, in the context of a suitable design of the
recoil lock (size and number of rolling elements, slope of locking
surfaces that become effective upon backward rotation, number and
size of the teeth of a ratchet tooth set, etc.), to limit any
recoil play of upper back part 5 (motion back opposite to pivot
direction S toward the normal use position of back part 5) to a
maximum angular magnitude of approximately 1 degree.
[0054] The embodiment according to FIGS. 3 and 4 shows an
embodiment of immobilization means 10 for retention of upper back
part 5, in particular crossmember 5a, as a snap-locking ratchet
mechanism. A carrier element 10a for at least one, and in the
embodiment depicted for two ratchet tooth sets 10b, 10c is attached
within the pocket-shaped holding part 6b. The respective tooth set
10b, 10c coacts with at least one, and in the embodiment depicted
with two teeth 4e, 4f on support part 4d, functioning as
counterpart ratchet elements. The two tooth sets 10b, 10c and the
corresponding counterpart teeth 4e, 4f, which are each offset from
one another, result in greater security for the ratchet connection,
and in a reduction (by half) in the recoil play of upper back part
5.
[0055] The embodiment as depicted in FIG. 5 shows a configuration
of immobilization means 10 for retention of upper back part 5, in
particular crossmember 5a, as a rolling-element locking device.
This rolling-element locking device comprises a ring gear 10d,
arranged concentrically about pivot axis X-X of upper back part 5,
that is arranged inside a cylindrical shell 10e; and rolling
elements 10g arranged between teeth 10f of ring gear 10d and
between ring gear 10d and shell 10e. Torsion spring 6a is immovably
joined to ring gear 10d. The tooth flanks of teeth 10f of ring gear
10d are embodied in such a way that the rolling-element locking
device permits pivoting (pivoting direction S) into the safety
position of upper back part 5 and into the interception position of
headrest 8, since rolling elements 10g can roll freely between ring
gear 10d and shell 10e; whereas in the event of a motion in the
opposite direction, jamming of rolling elements 10g between ring
gear 10d and shell 10e occurs and inhibits this backward
motion.
[0056] A similar principle is also the basis of the embodiment of
the recoil lock depicted in FIG. 6. This differs from the
embodiment described above, however, in that rolling element or
elements 10g are each under the load of a spring 10h, and that what
comprises receptacles 10k for rolling elements 10g is not an inner
part 10i corresponding to ring gear 10d and arranged concentrically
about pivot axis X-X of upper back part 5, but rather a shell part
10l corresponding to cylindrical shell 10e. The manner of operation
of this device corresponds to that described above. The walls of
receptacles 10k of shell part 10l are embodied in such a way that
the rolling-element locking device permits pivoting (pivoting
direction S) into the safety position of upper back part 5 and into
the interception position of headrest 8, since rolling elements 10g
can roll freely between inner part 10i and shell part 10l against
the action of spring 10h; whereas in the case of a motion in the
opposite direction with the effect of spring 10h additionally
acting in that direction, jamming of rolling elements 10g occurs
and inhibits this backward motion.
[0057] The embodiment of recoil lock depicted in FIG. 7 differs
from that shown in FIG. 6 in that jamming wedges 10m are used
instead of rolling elements 10g.
[0058] In the embodiment of the recoil lock depicted in FIG. 8, as
in the two previous embodiments, a cylindrical inner part 10i
having a smooth enveloping surface (or also one structured to
increase friction, or equipped with a coating) is provided; but in
the event of the backward motion described above, jamming is
performed by means of at least one eccentrically mounted pivoting
body 10n engaging nonpositively on the enveloping surface of inner
part 10i.
[0059] As already mentioned, FIGS. 9 and 10 show two views of an
upper part 5 of a further preferred embodiment of a seatback 2
according to the present invention. In this embodiment, the lever
system of immobilization means 9 for retention A of upper back part
5 in the normal use position comprises a interlock lever 9h,
immovably joined to upper back part 5, in particular via a holder
11 to crossmember 5a of back part 5, and to torque-generating
device 6. In the embodiment shown, said lever is configured in
particular as an angled lever pivotable about pivot axis X-X of
upper back part 5, and is secured in a locked position (shown in
FIGS. 9 and 10) by a locking bolt 9i. For that purpose, in the
locked position locking bolt 9i engages through an opening 9k in
one angled limb of interlock lever 9h, while the other angled limb
is joined to torsion spring 6a. In the event of a crash, locking
bolt 9i can be moved out of opening 9k in order to release
torque-generating device 6 (concretely, torsion spring 6a).
[0060] Means 7 for detecting the rear-end impact are in effective
connection U with immobilization means 9 for retention A of upper
back part 5 in the normal use position (in the instance depicted,
with locking bolt 9i), and immobilization means 9 (concretely,
locking bolt 9i and interlock lever 9h) are in effective connection
B with torque-generating device 6 (torsion spring 6a), in such a
way that in the event of the impact, a release of torque-generating
device 6 is initiated by immobilization means 9 pyrotechnically,
i.e. preferably by means of a priming cartridge. Pyrotechnic device
12 serving this purpose can, as depicted, be arranged in holder 11
for locking bolt 9i.
[0061] In addition, unlike in the embodiments depicted previously,
in the embodiment depicted in FIGS. 9 and 10 a special recoil lock
13, by way of which interlock lever 9h is joined to torsion spring
6a, is provided. This recoil lock 13 serves as an assembly aid, and
blocks any pivoting of upper back part 5 in direction S out of its
normal use position into its safety position, but permits pivoting
in the opposite direction. Recoil lock 13 can be embodied as a
self-locking rolling-element or wedge-type lock that operates
positively and/or nonpositively (preferably by jamming), or as a
ratchet device, in such a way that it makes possible immobilization
even in positions located between the safety position and the
normal use position of upper back part 5. In detail, recoil lock 13
can be configured in the same way as immobilization means 10
(described above) for retention K of the upper back part against
backward motion out of the safety position into the normal use
position, except that it acts in the opposite direction. Recoil
lock 13 can advantageously result in easier assembly, for example
in that locking bolt 9i is first inserted into opening 9k of
interlock lever 9h, which for that purpose can preferably be
configured as an elongated hole, and then torsion spring 6a is
tensioned (opposite to direction S) with a tool; in this context,
recoil lock 13 permits this tensioning, but prevents any undesired
springing back (relaxation) of torsion spring 6a. Such relaxation
of torsion spring 6a is possible in the event of a crash, however,
since after the removal of locking bolt 9i, interlock lever 9h that
is held in place on torsion spring 6a by the recoil lock can also
be moved.
[0062] As is already evident from the description above, the
invention is not limited to the exemplary embodiments depicted, but
also encompasses all embodiments that are functionally identical
for purposes of the invention. For example, the lever system could
also be embodied in a manner different from that depicted and
described, and arranged elsewhere. As regards the depictions in the
drawings, FIGS. 6 through 8 are depicted partially schematically.
With regard to further possible details of seatback 2 according to
the present invention and a method implementable therewith for
preventing accident-related injuries to a seat user, the reader is
referred to German Patent Application 199 38 904.7 mentioned
earlier, in its entirety.
[0063] The invention furthermore is also not limited to the
combination of features defined in claim 1, but rather can also be
defined by any other desired combination of specific features of
all the individual features disclosed globally. This means that in
principle practically any individual feature of claim 1 can be
omitted and replaced with at least one individual feature disclosed
elsewhere in the Application. Claim 1 is in this respect to be
understood as merely a first attempt at stating an invention.
* * * * *